Slip control systems of hydraulic vehicle brake systems have hydraulic units with hydraulic components for slip control. Such hydraulic components are solenoid valves, check valves, hydraulic pumps, hydraulic accumulators, damper chambers and restrictors. For mechanical fastening and hydraulic interconnection of the hydraulic components, such hydraulic units have hydraulic blocks. The hydraulic blocks are normally cuboidal flat blocks made of metal, e.g. an aluminum alloy. Sockets for the hydraulic components are formed in the hydraulic blocks, typically being embodied as blind holes of stepped diameter into which the hydraulic components are inserted, pressed or installed in some other way and fastened, for example, by swaging. Lines are produced by drilling the hydraulic block, said lines extending predominantly parallel to edges of the hydraulic block, i.e. in a Cartesian pattern, and hydraulically interconnecting the sockets and the hydraulic components installed therein. A hydraulic block equipped with the hydraulic components for slip control can be understood as a hydraulic unit.
The hydraulic block or hydraulic unit is connected to a brake master cylinder by brake lines, and hydraulic wheel brakes are connected to the hydraulic unit or hydraulic block by brake lines.
European Patent EP 1 623 118 B1 discloses a hydraulic block of this kind for an antilock control system in a hydraulic vehicle brake system, having a pressure change damper which is arranged in a socket in the hydraulic block and communicates via a connecting line produced as a hole with an outlet of a piston pump, which is likewise arranged in a socket in the hydraulic block. At the same time, the pressure change damper communicates via the outlet of the piston pump with an isolation valve, by means of which the hydraulic unit is connected to a brake master cylinder, and with brake pressure buildup valves, by means of which the wheel brakes are connected to the hydraulic unit. The pressure change damper is used to damp pressure surges, pressure pulsation and pressure oscillations of brake fluid at the outlet of the piston pump. The pressure change damper of the known hydraulic unit has just one port and no separate inlet and outlet.